In this 7 minute talk, the 3 reasons (hearing sensitivity, room acoustics, mixdown) a sensible amplifier always needs to have tone controls or an equalizer, and how taking that into account, the resolution
loudspeaker allows the most un-adulterated experience.

In this 7 minute talk, a practical demonstration, calculation and explanation of
why the distance between sound sources from a loudspeaker, determines if nearly all the frequencies get audibly distorted, or in the case of the resolution - not at all.